Method and an apparatus for scalding slaughtered poultry

ABSTRACT

A method and an apparatus for scalding of slaughtered poultry are described, for example chickens, hens, turkeys, ducks, or geese, prior to plucking thereof, where the birds while shackled by their feet are conveyed through a scalding chamber ( 2 ), preferably via a sluice device, in which chamber a precisely controlled heated atmosphere of humid, hot air is established by blowing in steam at the bottom of the scalding chamber, which air is recirculated and blown directly onto the poultry, and where the scalding period is determined by the length and course of the conveyor ( 8 ) and by the capacity and/or speed of the conveyor, where a scalding chamber ( 2 ) with a relatively large height is used, and where the scalding chamber conveyor ( 8 ) including its secondary nozzles ( 10 ) extends through two or more levels (stories).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a method for scalding of slaughteredpoultry, for example chickens, hens, turkeys, ducks, or geese.

2. Description of the Prior Art

For scalding of slaughtered poultry prior to plucking, to make thefeather follicles soft in order to facilitate plucking, it is known thatbirds shackled by their feet are successively led down through an oblongvessel containing hot water, maybe combined with the blowing in of airthrough nozzles placed at the bottom.

EP-A1-1 297 748 describes a method and an apparatus for scalding ofpoultry where saturated air is blown in at the bottom of the scaldingchamber by means of a primary nozzle arrangement, which saturated steamis used for producing moist, hot air, which is sucked out at the top ofthe scalding chamber and reblown directly onto the poultry by means of asecondary nozzle arrangement. Although saturated steam is used forheating up the scalding air, it is nevertheless possible with thismethod to work with a low scalding temperature of approximately 50° C.or with a higher scalding temperature of approximately 60° C., in thatthe poultry is not directly exposed to saturated steam at any time.

The advantage of applying humid, hot air is a considerable energy savingand reduced spreading of bacteria. Furthermore a better working climatein the surrounding plucking room is achieved because of considerablyreduced steam generation. The poultry must be in the scalding chamberfor a specified period of time which is determined by the length and thecourse of the conveyor belt in the scalding chamber, and the capacityand/or speed of the conveyor belt. In order to utilize the space in thescalding chamber in an optimum way, the conveyor belt extends forwardsand backwards in parallel lengths inside the scalding chamber at thesame level.

SUMMARY OF THE INVENTION

The invention is an improved method for scalding of slaughtered poultry,and which in a simple way makes it possible to increase the scaldingcapacity of a given scalding system or apparatus considerably.

The method according to the invention utilizes a scalding chamber with arelatively large height with a scalding chamber conveyor, includingnozzles, extending through two or more levels (stories). In a simple wayit hereby becomes possible to increase the scalding capacity of a givenscalding system or scalding apparatus considerably. Most oftenrestrictions are with regard to space, that is, it is not possible toincrease the scalding capacity right away just by increasing the widthor the length of the scalding chamber.

In such a case, it is very important that the scalding capacity can beincreased within the space given by using a scalding chamber withconveyors and nozzles at two or more levels (stories), in thatscalding/plucking rooms normally have a sufficient ceiling height thatallows for a relatively high scalding chamber being provided withconveyor including its nozzles at several levels (stories). A scaldingprinciple of a closed scalding chamber with steam-saturated atmosphereis used in preference to the well-known scalding principle of a heatedwater bath into which the poultry is immersed, which increases thescalding capacity by using a higher, closed room with steam-saturatedatmosphere.

Since the scalding chamber primarily is a closed chamber, which can bebuilt of isolated panels, a scalding chamber according to the inventionis placed externally in the form of an additional building to anexisting poultry slaughterhouse, so that the scalding chamber does nottake up space in the scalding/plucking room. Such an external scaldingchamber can be provided with entry and exit sluices built into the wallof the usual scalding/plucking room.

Furthermore, the use of a high internal or external scalding chambermakes it possible to use the conveyor of the scalding chamber forconveying the poultry between two stories of a given slaughterhousebuilding in which for example a reception and slaughtering line isplaced at a lower floor, and where for example a plucking line is placedat an upper floor, or vice versa.

In order to optimize the scalding of the poultry, it may be especiallysuitable that the method according to the invention is modified in sucha way that two or more scalding chambers with mutually differenttemperature zones are used.

The method according to the invention may be further modified so that ashort first zone having an extra high temperature is used, for examplein the range of approximately 85° C. so that an efficient anti-bacterialtreatment of the poultry can be achieved.

For scalding of poultry, so-called low-temperature scalding orhigh-temperature scalding is used, the scalding temperature inlow-temperature scalding being approximately 50° C., and the scaldingtemperature in high-temperature scalding being approximately 60° C. Forexample, normally low-temperature scalding is used for poultry sold asfresh food, and where it is important that the outer skin is as intactas possible; while normally high-temperature scalding is used forpoultry sold as frozen products, and in which case it is less importantwhether the outer skin is intact or not.

By using scalding apparatuses or systems with several temperature zones,for example a first zone having a scalding temperature of approximately60° C., and a second zone having a scalding temperature of approximately50° C., not only increased capacity is achieved, but also a milderscalding effect in the second zone is achieved, so that the outermostskin layer of the poultry is at all times treated as carefully aspossible. It is furthermore important that scalding is optimized in sucha way that lower skin and meat are not too strongly exposed to heat.

The invention furthermore relates to an apparatus for use when applyingthe method according to the invention, the apparatus comprising ascalding chamber with a conveyor having a course with a number ofpreferably mutually parallel lengths, and comprising entry and exitsluices, which conveyor extends past a system of secondary nozzles forblowing humid, hot air directly on poultry passing the secondary nozzleson the conveyor, which apparatus comprises a system of primary nozzlesfor blowing in steam at the bottom of the scalding chamber for producingan atmosphere of humid hot air, which air is recirculated via thesecondary nozzles, which apparatus has a scalding chamber withsubstantial height, and the scalding chamber conveyor, including thesecondary nozzles, extend through two or more levels (stories), and thatthe entry and exit sluices preferably are placed at different levels(stories).

In order to make it possible to optimize scalding, the apparatusaccording to the invention may suitably be provided with severalscalding chambers each having its own temperature zone, for example afirst scalding chamber with a scalding temperature of approximately 60°C., and a second scalding chamber with a scalding temperature ofapproximately 50° C.

In order to be able to achieve an efficient anti-bacterial treatment ofthe poultry, the apparatus according to the invention may furthermore beprovided with a short first zone having a higher scalding temperature ofapproximately 85° C.

In order to make it possible to utilize an existing scalding/pluckingroom in the best possible way, the apparatus according to the inventionmay be designed in such a way, that the scalding chamber is placedexternally, preferably as an additional building to an existingslaughterhouse, and that the entry and exit sluices preferably are builtinto an outer wall of the slaughterhouse.

The apparatus according to the invention may furthermore advantageouslybe designed in such a way that the scalding chamber extends between twostories of a slaughterhouse building. Thus the conveyor of the scaldingchamber can be used for conveyance of the chickens between two storiesof a slaughterhouse.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described in more detail below in connection with thedrawing in which

FIG. 1 shows a schematic outline of a longitudinal section of anembodiment of a scalding chamber according to the invention;

FIG. 2 shows a cross-sectional view of a known scalding chamber with onelevel (story);

FIG. 3 shows a sectional view for illustration of a scalding chambersystem having several temperature zones;

FIG. 4 shows a longitudinal sectional view and a cross-sectional viewrespectively of a known scalding chamber with one level (story); and

FIG. 5 shows a longitudinal sectional view and a cross-sectional viewrespectively of an embodiment of a scalding chamber according to theinvention with two levels (stories).

The scalding chamber 2 shown in FIG. 1 may for example have a width ofapproximately 2.5 in and a length of approximately 16 m whichcorresponds to a capacity of for example 3000 turkeys per hour with ashackle distance of 12 inches and a scalding period of 4 minutes. Thescalding chamber 2 has an entry sluice 4 and an exit sluice 6. In orderto achieve optimum utilization of the space in the scalding chamber 2, aconveyor 8, which comprises a system of secondary nozzles 10 on nozzlepipe 11, extends through this scalding chamber in mutually parallellengths 12 with narrow turning curves 14 between the lengths 12.

FIG. 2 shows the arrangement of a scalding chamber 14 known per se, justas it shows the secondary nozzles 10. The figure also shows how thehumid hot air, produced by blowing in steam through lower, primarynozzles 13 is recirculated by means of fans 16 placed on top of thescalding chamber 14, and which fans supply humid hot air to thesecondary nozzles 10 via the nozzle pipes 11, which air is blowndirectly onto the poultry.

FIG. 3 shows how a scalding system 18 may comprise several separatescalding chambers 20 and 22 each having its own temperature zone, inthat a first scalding chamber 20 having an entry sluice 21 works withsteam-saturated air at approximately 60° C., while a second scaldingchamber 22 having an exit sluice 23 works with steam-saturated air atapproximately 50° C. Both scalding chambers 20 and 22 can be constitutedby high scalding chambers according to the invention, that is, withseveral levels (stories).

FIG. 4 shows a longitudinal sectional view and a cross-sectional viewrespectively of a known scalding chamber with one level (story), whileFIG. 5 shows a longitudinal sectional view and a cross-sectional viewrespectively of an embodiment of a scalding chamber 2 according to theinvention, that is, with two levels (stories), arranged tiered, that is,one above another as shown in the cross-sectional view of FIG. 5, eachlevel being provided with secondary nozzles 10 and primary nozzles 13,cf. the nozzle arrangement known per se, shown in FIG. 2.

1. An apparatus comprising at least one scalding chamber, a conveyor forconveying poultry in one of the at least one scalding chamber having acourse with parallel lengths including entry and exit sluices, theconveyor extending past second nozzles for blowing humid, hot airdirectly on the poultry passing the second nozzles on the conveyor,first nozzles for blowing in steam at a bottom of the one of the atleast one scalding chamber for producing the humid, hot air which air isrecirculated via the second nozzles, and wherein the conveyor in the oneof the at least one scalding chamber extends through at least two tieredconveyor levels therein past the second nozzles.
 2. An apparatusaccording to claim 1 wherein the entry and exit sluices are placed atdifferent levels of the one of the at least one scalding chamber.
 3. Anapparatus according to claim 2, comprising scalding chambers each havinga temperature zone, with a first scalding chamber for providing ascalding temperature of approximately 60° C., and a second scaldingchamber for providing a scalding temperature of approximately 50° C.